Paving the Road to Zero Waste at Toyota’s Indiana Plant

How do you turn manufacturing sludge into a sustainable building material? Toyota Motor Manufacturing, Indiana (TMMI) offers a “concrete” example.

Before 2010, water used in the manufacturing process was pumped into the plant’s wastewater treatment system. It was cleaned and treated with a chemical — ferric sulfate— to remove metals and contaminants. The result: a useless iron-rich sludge left behind as waste…a LOT of waste. Sludge was nearly 70 percent of TMMI’s total waste stream each month.

Enter Toyota’s ongoing commitment to eco-efficient operations. To minimize waste and conserve natural resources, TMMI tested different additives in order to find a more natural way to treat the sludge from TMMI’s wastewater streams and the paint shop. Lime slurry, a non-hazardous mineral and more cost-effective alternative, performed the best. It reduced wastewater sludge by 4 pounds per vehicle, the equivalent of eliminating over 1 million pounds of wastewater sludge each year.